With the basic support framework now in place, it's time to finish up the floor supports.

Access to the tree house will be by a trapdoor. Here you see the frame for the trapdoor completed. Note the two
half-inch eye bolts (where the top of the ladder is leaning). These will hold the rope ladder that will be the way up
into the tree house.

Note also the extensive use of Simpson ties. In my opinion, Mr. Simpson is a
great benefactor of humanity, or at least of that portion of humanity engaged in building tree houses.

Also at this stage, extra supports and stretchers are added to the floor support structure.

I am getting into the zone now where I have to think about trading weight for strength. These additional supports are
not 2×6, they are 2×4; strong enough for what they have to do, without being unnecessarily heavy.

Now I can lay down the floor.

Because there are tree limbs coming up through the floor, this needs some thought. What I did was go up and make a
template — laying down a "floor" made of flattened-out old cardboard boxes (mostly from the Gerber company,
it seems). These I could easily cut and patch around the tree limbs, and duct-tape together to make a template.

Once the template was complete, I made a couple of strategic cuts to get it into two pieces, took it down to the
garage, and laid it out on a sheet of half-inch ply. Then I just drew on the ply with a magic marker where the
necessary holes (including a big square one for the trapdoor) need to be.

Here is the first of the eventual four floor sections in place. (And the second, too,
actually — you can just see a bit of it at bottom left.)

This section contains the north and east sides of the trapdoor opening, and half the south side, and half the west
side. You can just see the join (between first and second floor sections, that is) on the south side of the trapdoor
opening (bottom left of the picture). The next frame makes it a bit more clear.

The first section of floor is a big slab of half-inch ply, just too big for one man to schlep up a ladder. I therefore
hoist it up, using a rope slung over a tree branch as a pulley.

Here's another view of the first two sections in place. You can just make out the line where they
join. It runs through the dark shadow at the left of the big bole, then runs between that bole and the branch, then
turns sharp right to bisect the south side of the trapdoor opening. It also bisects the west side.

I found I needed an extra under-floor support in place, so I put one in perpendicular to the main line of the join.
It's as well to check the need for additional supports before you nail down the floor.

Here goes with making a template for the third section (and a bit of the fourth). Again, it's
just cut-up cardboard boxes and duct tape.

You can see part of the first section at the left.

Here's the third flooring section in place, seen from the south. The hammer is lying on the first
section.

The third flooring section in place, seen from the east.

Now the fourth and last section of the flooring is in place. The join with the third section is
so good you can hardly see it.
The fourth section is most of a 4ft by 8ft sheet of half-inch ply. This was heavy — much too heavy to bring
up the ladder, and almost too heavy to pull up with a rope. I was on the point of asking neighbors to help, but
somehow I made it. This whole thing is a one-man project.

All the flooring is now in place.

This is a view from below, to the north.

Notice that the flooring overhangs the frame in places. The next thing I shall do is just trim off these overhangs,
like a pie crust, using a power saw. I also need to add a couple more minor supports underneath, where the ply is not
sufficiently supported. Then the flooring work will be complete.

When I started Phase 2 I intended to include the trapdoor and rope ladder as part of it. However, I have decided to
defer those to the end, and get on with building walls and roof. This, therefore, is the …